A new study says basic prescription drug coverage could vary dramatically from state to state under President Barack Obama's health care overhaul.

That's because states get to set benefits for private health plans that will be offered starting in 2014 through new insurance exchanges.

The study out Tuesday from the market analysis firm Avalere Health found that some states will require coverage of virtually all FDA-approved drugs, while others will only require coverage of about half of medications.

Consumers will still have access to essential medications, but some may not have as much choice.

Connecticut, Virginia and Arizona will be among the states with the most generous coverage, while California, Minnesota and North Carolina will be among states with the most limited.